Server identification in storage networks

1. A method for providing a host identifier for a host comprising: sending, from the host to a data storage system, a plurality of management requests defining what storage of the data storage system is accessible to the host over which one or more paths, wherein said plurality of management requests are used in connection with defining a topology of a storage area network including connectivity between the host and the data storage system, said sending including sending a management request of said plurality of management requests that includes the host identifier over a first path to the data storage system, said host identifier being formed using a first portion and a second portion, said host identifier being used to uniquely identify said host in the storage area network, said first portion including a first identifier associated with a system image for the host, said second portion including a second identifier generated in accordance with a hardware property of said host, wherein sending said management request over a particular path to the data storage system defines said particular path as an allowable path in the topology over which the host can access storage of the data storage system; receiving, by the data storage system, said management request over said first path from the host; performing, by the data storage system in response to receiving said management request over the first path identified by a first sending port identifier of a first sending port of the host from which the management request is sent and a first receiving port identifier of a first receiving port of the data storage system at which the management request is received, processing to define said first path as an allowable path in the topology over which a host having the host identifier can access a portion of storage of the data storage system by issuing subsequent data requests over the first path, said processing including storing information about said host in an access control table used in determining whether to allow a data request received by the data storage system, said information including said host identifier, said first sending port identifier and said first receiving port identifier for the first path, and identifying the portion of storage; receiving, at a second receiving port of the data storage system, a second management request from a second host having a second host identifier, said second management request being sent over a second path defined by a second sending port identifier of a second sending port of the second host and a second receiving port identifier of the second receiving port; and determining a degree of difference between corresponding portions of second information and first information, wherein said second information includes the second host identifier, said second sending port identifier, and said second receiving port identifier and wherein said first information includes said host identifier, said first sending port identifier and said first receiving port identifier, wherein said determining a degree of difference includes determining whether the second information is associated with the host or a different host, and determining whether a host bus adapter which is included in the host and includes said first sending port has been replaced in said host with a new host bus adapter.

2. The method of claim 1 , wherein said first identifier is produced using software executed on said host.

3. The method of claim 1 , wherein said first identifier is user specified.

4. The method of claim 1 , wherein said first identifier is generated using a network address of said host and at least a portion of a timestamp.

5. The method of claim 1 , wherein said hardware property is an address associated with a hardware component of said host, and wherein said hardware component is a network interface card and said address is a unique address assigned to said hardware component when manufactured.

6. The method of claim 1 , wherein a third of said plurality of management requests received over a third path at said data storage system defines said third path as another allowable path in addition to said first path over which a host having the host identifier can access the portion of storage by issuing a subsequent data request over the third path, and wherein a fourth of said plurality of management requests received on a fourth path at said data storage system defines a path deletion and causes the data storage system to update the access request table by deleting said fourth path as an allowable path to access storage of the data storage system for a host having the host identifier.

7. A method for processing a management request comprising: receiving, at a data storage system from a host, a plurality of management requests defining what storage of the data storage system is accessible to the host over which one or more paths, wherein said plurality of management requests are used in connection with defining a topology of a storage area network including connectivity between the host and the data storage system, said plurality of management requests including a management request received at a second connectivity point of the data storage system from a first connectivity point of the host, said management request including an associated host identifier identifying said host and being associated with a second identifier identifying said first connectivity point and a third identifier identifying said second connectivity point, said management request being sent by said host over a path defined by said first connectivity point and said second connectivity point and defining said path as an allowable path in the topology over which the host can access storage of the data storage system, said host identifier including a first portion that varies with software installed on the host and a second portion that varies with a hardware property of the host; and performing, by the data storage system in response to receiving the management request over the path, processing to define the path as an allowable path in the topology over which a host having the host identifier can access a portion of storage of the data storage system by issuing subsequent data requests over the path, said processing including storing in an access control table said host identifier, said path and identifying, a portion of storage, said processing including determining, by said data storage system in accordance with data including said host identifier, said third identifier and said second identifier associated with the management request, if there is an existing entry in the access control table corresponding to first information including the portions of the host identifier, said second identifier and said third identifier, said determining including: identifying one of a plurality of cases indicating a degree of correspondence between an existing entry in said access control table and the first information, wherein said access control table associates a portion of storage and one or more paths with each host identifier stored therein, at least a first of said one or more paths for said each host identifier being a path over which a management request has been received by said data storage system from a host having said each host identifier, said access control table indicating that a subsequent data request to access a storage device in said portion is allowed when the subsequent data request is received by the data storage system over any of said one or more paths from a host having said each host identifier; and determining an inference based on said degree of correspondence between the existing entry and the first information, said determining an inference including determining whether the degree of correspondence indicates that a host bus adapter which is included in the host and includes said first connectivity point has been moved to another host, and determining whether the degree of correspondence indicates that a host bus adapter which is included in the host and includes said first connectivity point has been replaced in said host with a new host bus adapter.

8. The method of claim 7 , wherein said first portion of the host identifier is generated in accordance with an identifier associated with a system image of the host.

9. The method of claim 8 , further comprising: determining differences between entries in said access control table and said host identifier; and performing an action based on any determined differences.

10. The method of claim 9 , further comprising: determining that said host is a new host if an entry in said access control table does not include information corresponding to said second identifier and said second portion of said host identifier.

11. The method of claim 9 , further comprising: determining that a hardware component of said host having said hardware property has been replaced if an entry in said access control table includes information corresponding to said second identifier and said first portion of said host identifier, and does not include information corresponding to said second portion of said host identifier, and updating entries in said access control table for said host to include said second portion.

12. The method of claim 9 , further comprising: determining that a new host bus adapter has been installed at said host if an entry in said access control table includes information corresponding to said first and second portions of said host identifier, and does not include information corresponding to said second identifier associated with said first connectivity point, and accordingly updating entries in said access control table.

13. The method of claim 9 , further comprising: determining that a host bus adapter associated with said first connectivity point of said host has been included for use with another host if there is an entry in said access control table including information corresponding to said second identifier, and the entry does not include information corresponding to said first and second, portions of said host identifier.

14. The method of claim 9 , further comprising: determining that a hardware component of said host having said hardware property has been included for use with another host if an existing entry in said access control table includes information corresponding to said second portion of said host identifier and said entry does not include information corresponding to said first portion of said host identifier and said second identifier.

15. The method of claim 9 , further comprising: determining that said host has been reinstalled, or that a hardware component of said host having said hardware property and another hardware component associated with said first connectivity point have been moved to another host from said host if an existing entry in said access control table includes information corresponding to said second portion of said host identifier and said second identifier and the entry does not include information corresponding to said first portion of said host identifier.

16. The method of claim 7 , further comprising: performing an action in accordance with a policy and in accordance with said one of the plurality of cases selected by said determining, said policy indicating whether said action is to be performed without further user interaction.

17. A computer program product including a non-transitory computer readable medium comprising code stored thereon for providing a host identifier for a host, the non-transitory computer readable medium comprising code that: sends, from the host to a data storage system, a plurality of management requests defining what storage of the data storage system is accessible to the host over which one or more paths, wherein said plurality of management requests are used in connection with defining a topology of a storage area network including connectivity between the host and the data storage system, said sending including sending a management request of said plurality of management requests that includes the host identifier over a first path to the data storage system, said host identifier being formed using a first portion and a second portion, said host identifier being used to uniquely identify said host in the storage area network, said first portion including a first identifier associated with a system image for the host, said second portion including a second identifier generated in accordance with a hardware property of said host, wherein sending said management request over a particular path to the data storage system defines said particular path as an allowable path in the topology over which the host can access storage of the data storage system; receives, at the data storage system, said management request over said first path from the host; performs, by the data storage system in response to receiving said management request over the first path identified by a first sending port identifier of a first sending port of the host from which the management request is sent and a first receiving port identifier of a first receiving port of the data storage system at which the management request is received, processing to define said first path as an allowable path in the topology over which a host having the host identifier can access a portion of storage of the data storage system by issuing subsequent data requests over the first path, said processing including storing information about said host in an excess control table used in determining whether to allow a data request received by the data storage system, said information including said host identifier, said first sending port identifier and said first receiving port identifier for the first path, and identifying the portion of storage; receives, at a second receiving port of the data storage system, a second management request from a second host having a second host identifier, said second management request being sent over a second path defined by a second sending port identifier of a second sending port of the second host and a second receiving port identifier of the second receiving port; and determines a degree of difference between corresponding portions of second information and first information, wherein said second information includes the second host identifier, said second sending port identifier, and said second receiving port identifier and wherein said first information includes said host identifier, said first sending port identifier and said first receiving port identifier, wherein determining a degree of difference between the first information and the second information includes determining whether the second information is associated with the host or a different host, and determining whether a host bus adapter which is included in the host and includes said first sending port has been replaced in said host with a new host bus adapter.

18. The computer program product including the non-transitory computer readable medium of claim 17 , wherein said first identifier is produced using software executed on said host.

19. The computer program product including the non-transitory computer readable medium of claim 17 , wherein said first identifier is generated using a network address of said host and at least a portion of a timestamp.

20. The computer program product including the non-transitory computer readable medium of claim 17 , wherein said hardware property is an address associated with a hardware component of said host.